Mut‘a was practiced by Muslims during the time of the Prophet, for newly minted fighters far from home, but it was an on-again-off-again provision, having been allowed, then revoked by the Prophet three times. The rule was finally abrogated by ‘Umar, one of the Prophet’s companions and the third caliph, or leader, of the newly minted Muslim community in the 7th century; Shi‘i Muslims, who follow another early leader, ‘Ali (who was also the Prophet’s son-in-law) rejected this prohibition. It’s been bone of contention between the sects ever since, and a source of some envy among young Egyptians I know who wish their brand of Islam allowed such expediency. For more on the debate over the permissibility of muta‘ a marriage in Sunni Islam, see Hayrat Muslima [Confusion of a Muslim Woman] by Olfa Youssef.